Abstract: In order to study the effect of different withering degree on quality and catechin oxidation during Taishun black tea processing, the experiments used the way of natural withering, it set three different treatments named short withering, appropriate withering, long withering by monitoring water content of the withering leaf, it explored the change of tea polyphenols, catechins, theaflavins and theasinesins content during black tea processing. The research showed that the total score of sensory quality was appropriate withering＞short withering＞long withering, short withering treatment got the higher score of liquor colour and infused leaf; tea polyphenols and catechins content of withering leaf decreased with the withering time, and generated theasinesins and a small amount of theaflavins; catechins content decreased, theaflavins and theasinesins content decreased first then ascended during rolling and fermentation processing, comparing with different withering degrees showed that short withering treatment remained and oxidated more catechin and generated more theaflavins, long withering treatment remained and oxidated the least catechin and generated the least theaflavins, the amount of oxidating catechin and generating theaflavins of appropriate withering treatment were between short withering and long withering treatment.